The present invention relates generally to a foot pedal apparatus for a drum (hereinafter referred to also as “drum foot pedal apparatus”) which causes generation of a tone by pivoting a beater, in response to depression of a foot board, to thereby strike a drum with the beater.
Drum foot pedal apparatus have been known which generate a tone by pivoting a beater, in response to depression of a foot board, to thereby strike a drum head with the head of the beater. The conventionally-known drum foot pedal apparatus, as disclosed for example in Japanese Patent No. 2806301, include a pivot shaft having the beater mounted thereto, a pair of left and right support posts pivotably supporting the pivot shaft, and a transmission member, such as a chain, interconnecting the distal end of the foot board and the pivot shaft. According to the disclosure of the above-identified Japanese patent, a coil spring for normally urging or biasing the foot board toward an initial (non-depressed) position of the foot board (in other words, for imparting resilient self-returning force to the foot board) is connected to either or both of the opposite end portions of the pivot shaft. The coil spring is engaged at its upper end by a roller, via a link member, that is in turn rotatably supported on a crank arm, and the coil spring is engaged at its lower end in a through-hole of an adjusting screw (bolt).
Further, according to the disclosure of the above-identified Japanese patent, a tension adjustment mechanism is provided for adjusting the position of the adjusting screw. As shown for example in FIG. 6 of the above-identified Japanese patent, the tension adjustment mechanism comprises an adjusting nut for moving the adjusting screw upward or downward relative to a screw mounting member through rotation of the adjusting nut, and a locking nut for preventing loosening of the adjusting nut. The tension of the coil spring is adjustable by a human player or operator rotating the adjusting nut to thereby move the adjusting screw upward or downward.
Namely, the aforementioned coil spring tension adjustment mechanism allows the human player or operator to adjust the tension of the coil spring by operating the nut disposed on a lower end portion of the adjusting screw. As described for example in paragraph 0014 of the above-identified Japanese patent, in response to the human player or operator rotating the nut while holding a large-diameter portion of the nut with fingers, the adjusting screw moves along a screw hole (threaded hole) of the nut upward or downward, depending on the rotating direction of the nut, to thereby effect adjustment of the tension of the spring. Furthermore, Japanese Patent No. 3584898 discloses that the tension of a coil spring is adjusted by the human player or operator rotating an adjusting screw disposed below a bracket (support section).
In playing the drum with the foot pedal apparatus constructed in the aforementioned manner, the pivot shaft pivots via the transmission member in response to the human player depressing the foot board, so that the beater swings toward the drum head. Because, in response to the swing of the beater, the crank arm too moves upward with its distal end swinging upward, the coil spring engaged by the roller is expand, so that a load by the tension of the coil spring increases.
Furthermore, techniques related to drum foot pedal apparatus are also disclosed in U.S. Pat. Nos. 6,894,210, 9,236,038 corresponding to Japanese Patent Application Laid-open Publication No. 2016-95379, etc.
Because the coil spring tension adjustment mechanism employed in the aforementioned foot pedal apparatus is constructed to adjust the coil spring tension in response to the human player or operator operating the nut disposed on a lower end portion of the adjusting bolt as noted above, the bolt, the arm, the coil spring, etc. would get in the way of the tension adjusting operation and thus make it difficult to for the human player or operator to operate the nut, if the pedal apparatus is left placed on the floor. Although the nut can also be operated with the pedal apparatus tilted downward, extra operations for detaching the pedal from the drum etc. are required, and thus, such an operation of the nut is difficult to perform particularly in a case where the pedal apparatus is of a twin-pedal construction.
Further, an example of a support structure for supporting the coil spring in the aforementioned foot pedal apparatus is conventionally known in which the coil spring is engaged at its lower end by the distal end of a metal rod. However, with such a conventionally-known coil spring support structure, where the coil spring is engaged at its lower end by the distal end of a metal rod, durability of the foot pedal apparatus would decrease due to frictional wear resulting from sliding contact between respective metal engaging portions of the coil spring's lower end and the metal rod, and performance-related inconveniences may occur due to noise generated by the sliding contact.
As measures for avoiding the aforementioned inconveniences, it has been known to provide a rotation structure on the engaging portion located at the lower end of the coil spring such that sliding between the metal engaging portions caused due to swinging movement as the coil spring expands and contracts can be reduced but also excessive force can be prevented from acting on the adjusting screw due to the swinging movement. However, such measures are unsatisfactory in that the provision of the rotation structure at the lower end of the coil spring would increase the number of necessary component parts and complicate the construction of the foot pedal apparatus and accordingly increase the manufacturing cost of the apparatus.